In order to rehabilitate people who suffer from movement disorders, various kinds of therapies are employed such as neurotherapy, physical therapy, etc. Changes in motion capabilities, in general, can be obtained either by biomechanical changes (e.g., using drugs to build muscles, anaerobic, aerobic, performing work against force), or by repeated practice against a predetermined target, teaching and guiding, before, during or after the practice. Both theses techniques might be based on practicing the movement as it is, without any external facilities, or with facilities such as physicians, computer games, virtual reality, etc. Usually, these techniques are time consuming. Consequently, the capacity to handle therapy for example by physicians, who perform such therapies, is significantly limited.
It is noted that most of the existing devices of the kind specified are capable of mainly changing and possibly improving motion capabilities by biomechanical changes.
An example of the existing devices is disclosed for example in U.S. Pat. No. 4,354,676. According to this technique, an exerciser bar is supported for rotation and acts against an hydraulic cylinder with the angle of the bar and the pressure in the cylinder measured and fed to a micro computer which, using this input data, controls the cylinder pressure in accordance with a selected exercise program, the micro computer also providing outputs to displays so that the person exercising can monitor his progress.
U.S. Pat. No. 4,544,154 discloses a passive programmable resistance device that uses a closed loop feedback for controlling resistance to rotational or translational motion of an object. One or more actual parameters, such as force or position, are measured and compared with desired parameters. The differences are used to provide a control signal which controls the resistance to the movement of the object.
U.S. Pat. No. 5,466,213 discloses an interactive robotic therapist that interacts with a patient to shape the motor skills of the patient by guiding the patient's limb through a series of desired exercises with a robotic arm. The patient's limb is brought through a full range of motion to rehabilitate multiple muscle groups. A drive system coupled to the robotic arm is controlled by a controller which provides the commands to direct the robotic arm through the series of desired exercises. This robot is further described in a website http://www.interactive-motion.com/ and in a paper “Robot-Aided Neurorehabilitation”, Hermano Igo Krebs, Neville Hogan, Mindy L. Aisen, and Bruce T. Volpe, IEEE Transactions on Rehabilitation Engineering, Vol. 6, No. 1, March 1998.
U.S. Pat. No. 6,413,195 discloses a passive/active hydraulic exercise device having a base portion, an upright support and a pivot bard that is selectively placed in either a passive push and pull type resistance mode or an active velocity type mode. In the passive mode, a pump can be off or on during “idling”. A solenoid valve is energized to an open position, and a servo valve sets a resistance for the fluid flow in the system. A check valve compensates for the differential areas of the cylinder. The active mode is useful for physical therapy applications. In this mode, a constant cycling operation is provided at absolute minimum force levels. The load cell senses the actual force generated, and the position feedback senses actual movement of the exercise bar. As long as the subject is providing enough force to move the bar, the feedback device confirms movement to the computer which adjusts the resistance of the electronic pressure control valve to a value which will allow the subject to continue moving the bar. This force is measured by the load cell and controlled by the servo-valve.